Tap grinding machine



Sept. 18, 1934. E. c. OLIVER 1, 5

TAP GRINDING MACHINE FiledJan. 15, 1951 7 Sheets-Shet 1 INVENTOR. [00 CfiZ/Vaq A TTORNE Y.

Sept. 18, 1934. I 4c. OLIVER 1,974,365

TAP GRINDING MACHINE Filed Jan. 15, 1951 7 Sheets-Sheet 2 INVENTOR. [ppC $4 mcie A TTORNEY.

E8, 13 E Q QLIVER 1,974,365}

TAP GRINDING MACHINE Filed Jan. 15, 1961 7 Sheets-Sheet 3 A TTORNE Y.

Sept. 18, 19340 E. Q QLWER 1,974,365

TAP GRINDING MACHINE Filed Jan. 15. 1931 7'Sheets-Sheet 4 m n Q Q w, B3g 'IAYIIIIL A TTORNE Y.

Sept. 18, 1934. 5 ()LI'V'ER 1,974,365

TAP GRINDING MACHINE Filed Jan. 15 1931 7 Sheets-Sheet 5 ATTORNEY.

sept- 1934- E. C(QLJVER 1,974,365

'I'AP GRINDING" MACHINE Fild Jan. 15, 1931 ,7 Sheets-Sheet e Sepia 18,1934. Q OLIVER 1,974,365

TAP GRINDING MACHINE Filed Jan. 15. 1-931 7 Sheets-Sheet 7 7 fi Z \Z K\2 l I %Z Wm /J j r K 2 Z Z Z /d f 4 I N VEN TOR.

A TTORNE Y.

Patented Sept. 18, 1934 EN T F F ICE.

TAP GRINDING MACHINE Edd 0.. Oiiver, Adrian, Mich.

Application January 15,

1-4 Claims.

This invention relates to machines for. grinding taps, it being a.purpose of the invention to provide a machine that isadjustable to adaptthe same for grinding not only the ordinary ta.- pered tap but otherspecial forms as a plug tap, a gun tap. a bottoming tap, etc.

It is further an object of the inventionto provide a tap grinder ofsuchcharacter that two, three or four .lipped taps may be automaticallyground to form-that. is, providing. the proper taper at the entering enddepending upon the type of the tap and. grinding. the lip back of thecutting edge to-provide clearance inoperation.

Further features of the invention. are involved in the means forcausing. the automatic grinding of the lip to a predetermined extentback of the cutting edge and in the means whereby a tap of any number oflips may be ground automatically.

A further feature and object of the invention is to provide atapgrinding machine that is adjustable for use with any size or diameterof tap inv which the lip at its entering end is ground to any desiredtaper as is required for the purpose for which the tap is to be used andfurther it is a purpose of the invention to provide a machine that maybe adjusted for use in dressing the cutting face of a lip andthat. iscomparatively simple and inexpensive in form.

These and other objects and the several novel features of theinvention'are hereinafter more fully described and claimed, and a tapgrinding machine embodying my invention is shown in the accompanyingdrawings in Which- Fig. 1 is a side elevation of the machine.

Fig. 2 is a front elevation thereof.

Fig. 3 is a plan view.

Fig. 4 is an. enlarged section taken on line 4-4 of Fig. 3. t

Fig. 5 is an 5--5 of Fig. 3'.

Fig. 6 is an enlarged section taken on line 6-6 enlarged section takenon line of Fig. 3. a

Fig. 7 is a side elevation of a bottoming tap.

Fig. 8 is an end view thereof.

Fig. 9 is a side elevation ofaplug tap.

Fig. 10 is an end view thereof.

Fig. 11 is a side elevation of a tapered tap.

Fig. 12 is an end view thereof.

Fig. 13 is a side elevation of a gun tap.

Fig. 14 is an end View thereof.

Fig. 15 is a diagram showing the relation of the gauge or stop inpositioning the tap for the grinding operation.

Fig. 16 is a perspective view of the head oi the table 19 has a raised.circular boss portion the portion 25 on the table 19. As will be seen1931-, Serial No. 509,000 I Fig. 18- is across section taken on line18-18 of Fig. 2.

Fig. 19 is avertical section taken on line 19-19 of Fig. 2. a I

Fig- 20 is a vertical section taken on line 2020 Of Fig. 5'.

A- screw shaft 15 is threaded in a nut 13a secured. in. a longitudinalaperture 13b in the member 13 and the base portions 16 and the clampingmember 1'1- have an attached plate 17a engaging. a collar 171) on thescrew shaft whereby rotation of the screw shaft by the hand wheel 18causes the carriage 14 tobe moved toward or from the. pedestal on. themember 13.

The carriage 14 has a slide or table 19' movable longitudinally thereofby means of a screw shaft-'20 provided with a hand wheel or crank 2iwhich is rotatably secured in; the attached flange 19a of the table 19whereby rotation of the shaft'causes longitudinal movement of the table.The slide 19 has tapered side flanges 22 engaging complemen-tal edges ofthe carriage 14. The carriage 14 has a nut 23. at one end into which thethreaded shaft extends, anda nut 24 at the other end thereof permittingthe screw shaft-tobe mounted at either end of the carriage.

Rotation of the hand lever 21 causes move-- ment of the table 19longitudinally of the carriage 14 at a right angle to the direction ofmovement of the carriage 14 by the screw 15. The

thereon formed with afinished face to receive the circular plate 26.This plate is centrally aperturecl to receive the screw 27, whichextends through the plate 26 into a threaded aperture in in Fig. 1 theboss 25 extends outwardly on one side of the table l9 and the two parts25 and 26 are calibrated as at 28 for the purpose hereinafter stated.The part 26 isv rotatable on the screw 2'2 andby loosening the screw themember 26 andparts carried thereby, (hereinafter described), may beturned at any angle desired which may be determined by the calibrations2'8.

This portion 26 above described is formed with an extension or base 29which is spaced above the table as will beseen in Fig. 2 and is providedwithv an aperture in the ,outer end thereof to receive a shaft30 shownclearly in Fig. 4. This shaft 30 is secured in the aperture of the base29 as by means of a set screw 31 which holds the same from rotation andfrom longitudinal movement. The shaft extends outwardly from this basemember 29 and a head 32 is rotatably supported thereon. In this head isa spindle 33 upported in anti-friction bearings 34 and 35 positioned inopposite ends respectively of the head.

The spindle 33 has a coned forward end 36 and within this spindle is asleeve 37 having a coned face to seat in the conedend 35 of the spindleand a threaded end portion 38 to receive the chuck 39. The sleeve 3'2may have its coned end portion clamped in the coned end portion of theouter end thereof.

lon itudinal movement in the bearings; Also ad'- jac'ent this nut ll andsecured to the spindle is an index plate 42 having notches 4:3 in itsface to receive the pawl 44 which is pivoted at 45 to the head 32.Between this index plate izand the end of the head is a cylindricalcover rnember 46 for the spiral gear 4'7 which is secured to the spindle33. A worm 48 engages the spiral gear and is supported in a casting i9pinned or secured to the outer end of the fixed shaft 30 and the wormmay be operated by the handle 50.

The head 32 is formed of a base on'the shaft 30 and two upwardlyextending portions 51 and 52 at opposite ends which are recessed toreceivethe g: bearings 34 and 35 and on the spindle 33 between theseportions 51 and 52 of the head are-a series of earns 53, 54, 55 and 56which arein spaced relation longitudinally of the spindle. The cams 53,5e and 55 are of a shape for' use" with two, three and four lipped tapsrespectively'and the remaining cam 56 may be of any special shape asmight be required for a special shape of clearance or other diiferencein form required for some special purpose. g

It is to be'noted that this head and all the parts carried therebyincluding the spindle, index plate, spiral gear, chuck and the tapcarried thereby are supported by the head 32 and thus all of these partsmay oscillate as a unit on the shaft 30. I

As will be seen more clearly in Fig. 6 the base 29 has a square shaft 57secured therein extending outwardly parallel with the shaft 30, it beingsecured in the base 29 as by means of a screw 58 shown by dotted linesin Fig. 6. On square bar 57 is slidably mounted a frame 59 at the upperend of which is carried a roller 60 flanged to engage over oppositesides of a cam and thus when positioned in engagement with any cam ofthe group it is held from displacement by these flanges. It will beobserved 10136 clearly in Fig. 3 that the flanges 61 of the rollerextend into the spaces between the cams of which three only are shown inthis figure. As these cams are carried by the rotatable head meansis'provided to cause the cams to ie in pressure engagement with theroller. This means consists of a plunger 62 supported in'a recess 63provided in a portion 64 0f the head and a spring 55 tends to projectthis plunger it is positioned relative to the grinding wheel 5substantially as indicated In Figs. 15 and 16. The tap shown in Figs. 15and 16 is an ordinary right hand tap and to position the tap with thecutting edge in proper relation with the grinding wheel I provide agauge 67 which has at its upper end the cut away portion 68 on thecenter line of the machine and on its opposite side has a hanging lip 69the under face of which is also on the center line of the machine. sshown in Fig. 4 the gauge is mounted on the plate 70 formed with a slot71 to receive a fastening screw '72. This base permits the gauge to beturned at any angle-about the screw and is variable in its distance fromthe screw center. The gauge 6"! has a threaded end portion '73 extendingthrough an aperture provided in the end of the plate "7-3 and a nut '74secures the same in place.

-In operating the machine to grind a four lipped right hand tapered tap,the tap is first mounted in the chuck and clamped by the shank the sameas it is held in the tapping machine. When the tap has been clamped thehand nut or knob 40 is locked and the chuck revolved about its axisuntil the cutting edge of a lip of the tap rests on the cut away portion68 of the gauge 67. With the left hand tap the cutting edge will be inthe reverse position fr'omthat shown in Fig.

15 and is brought in contact with the under side of the flange 690i thegauge.

In either case the cutting edge of the opposite lip of the tap isexactly at the center height of the axis of rotation. When thisadjustment has been completed the latch 44 is dropped in the index plateat a designated notch marked zero (not here shown) and the hand nut 40then clamped tightly to maintain the tap in that position. The roller 60is then brought opposite the cam corresponding to the number of cuttingedges of the tap to be ground (in the above case cam 53) and it is to beunderstood that these cams are formed with two, three or four highpoints depending upon the number of lips with which the tap is provided,the cam 55 for the four-lipped tap being shown in Figs. 6 and 15 ashaving the high points a, b, c, and d. The spindle is then revolved byrotation of the screw 48 and thus the cam will roll against the rollerproducing an oscillating motion of the head 32 and the parts carriedthereby including the tap. Due to the position of the cutting edge ofthe lip of the tap with the wheel shown in Fig. 15, this oscillatingmotion causes the top to move toward the vertical face of the wheelwhich therefore grinds an eccentric relief from the cutting edge of thelip backwardly depending upon the contour of the cam.

The base 29 being swiveled on the bolt 27 permits any degree of taper atthe point of the tap as may be required either with the ordinary tap,

plug or bottoming taps. The carriage 14. can be moved longitudinally tobring the 'tap on any desired part oi the grinding wheel below thecenter line thereof. Rotation by the handle 50 brings the successivelips of the tap to be ground 11 in strict relation with the oscillatorymovement caused by the cam wheels, the gauge 67 during the grindingoperation being moved out of position.

The above description has been closely confined to the mechanism andarrangement of parts for v grindingthe ordinary right hand four-lippedtap,

ut, as will be evident from the foregoing and by 7 use of the proper camwheel, taps with different numbers of lips may be automatically groundwith 'a. greater or less the correct or desired relief or clearance backof the cutting edge and by variation of the base 29 about its axis andthrough or by means of the calibrations 28 the lips may be groundwithany degree of taper as may be required for the diiierent forms of taps.With the three-lipped gun tap shown in Fig. 13, the entering end of thetap may be taper ground after the manner described above relative to thefour-lipped tap; but-with this type of tap the cutting face of the lipat the entering end of the tap is usually ground at an angle to thelongitudinal axis of the tap as indicated at in Fig. 13 providing ameans for forcing the chips upwardly in the flute of the tap.

It will further be realized from the foregoing that the machine is soconstructed as to permit adjustment of the tap for operation on theunderside of the periphery of the grinding wheel or in grinding relationwith the corner between the vertical and peripheral face of the wheel.When adjusted as last stated and while the tap is held from rotation oroscillation of the table 19 by means of the screw 21 causes movement ofthe tap in a straight line across the face of the wheel whereby thecutting face of the lip may be ground on a straight line or the tap maybe positioned at such angle to permit the grinding of the face of thelip at an angle as indicated at '10 in Fig. 13. In this latter case thetap and the head therefor are held from oscillatory or rotativemovement'of the tap. The machine therefore is so constructed as to adaptthe same for the grinding of any portion of the tap in the desiredmanner, even for the purpose of grinding ofi the end ofthe tap at aright angle to its axis. "This latter result may be attained by swingingthe table 19 at a right angle to the position shown in Fig. 2 with theaxis of the table parallel with the axis of the grinding wheel and byoperation of the screw 18 move the table 19 bringing the end of the tapinto grinding relation with the wheel.

It will thus also be evident from the foregoing that the various objectsof the invention are attained by the described mechanism.

Having thus fully described my invention, what I claim and desire tosecure, by Letters Patent of the United States is- I 1. In a machine forgrinding taps having. a plurality of lips, a rotatable grinding wheel, atap holder, a pivoted base supporting the tap holder, means foradjusting the base about its pivot to thereby position the holder withthe longitudinal axis the tap at the desired angle to. the face of thewheel, means for varying the position of the pivot point of thebase toposition a desired length of the Lap for engagement with the wheel face,manual means carried by the base for turning the tap to bring the lipsthereof in succession to grinding relation with the wheel, and meanswhereby each lip. is ground to an increasing extent rearwardly of thecutting edge to provide clearance. I

2. In a' machine for grinding taps having a plurality of lips, arotatable grinding wheel, a tap holder, a pivoted base supporting theholder, means for adjusting the base about its pivot to post on the tapwith the lip thereof for grinding relation with the wheel, means forvarying the position or" the pivot point of the base to present lengthof the tap for the grinding operation, and means for moving the holderduring the grinding of the tap toward the grinding wheel whereby the lipis ground eccentrically to the axis of the tap to'provide clearance. a

3. In a machine for, grinding taps having -a pluplurality of lips, a

automatically operating rality of lips, a rotatable grinding wheel, atap holder, a pivoted base for the holder, means for adjusting the baseabout its pivot to position the tap in grinding relation with the wheel,means for varying the position of the pivot point of the base relativeto the axis of rotation of the wheel to position the desired length ofthe tap for engagement with the wheel face, means for rotating the tapwhereby the lips thereof are. brought successively to the grindingrelation with the wheel, means actuated by the means for rotating thetap to move the holder as each lip comes to grinding position toward thegrinding wheel to cause the face of the up to be ground'eccentrically tothe axis of the tap to provide clearance.

4. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel, a'tap holder, a pivoted base supporting theholder, manually operable means for rotating the tap to bring successivelips thereof to grinding relation with the wheel, means for adjustingthe pivot point of the base to vary the length of the tap to besubmitted for the grinding operation, a cam supported by-the holder onthe axis of rotation of the tap and operable through rotation thereof tomove the'holder toward the grinding wheel as each lip of the tap comesto grinding position and thereby cause the face of the lip to be groundeccentrically to the axis of the tap to provide clearance.

5. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel having a flat face, a tap holder, manual meansfor rotating the holder to bring the lips of the tap successively togrinding relation with the face of the grinding wheel, means actingautomatically through rotation of the holder to move the holder and taptoward the grinding wheel as each lip thereof is brought to grindingrelation therewith to cause'the face of each lip to be groundeccentrically to the axis of'the tap, a pivotal support for the holderpermitting adjustment to vary the angle of presentation of the tap tothe grinding wheeL'a slide for said pivotal support whereby the pivotalpoint for the holder may be varied in position toward or from the axisof rotation of the wheel whereby the length of the tap to be ground maybe determined by the angle of presentation of the tap to the wheel.

6. In a machine for grinding taps having a rotatable grinding wheelhaving a fiat face, a tap holder, a pivotal base supporting the'holder,a shaft carried by the base on which the holder is mounted foroscillation, manual means for rotating by rotation of the holder tocause an oscillation thereof on the shaft in timed relation with therotation whereby each the holder and tap, means lip of the tap is movedinto the face of the grinding wheel to an increasing extent back of thecutting edge to provide clearance, said pivoted base providing a meansfor varying the angle of presentation of the tap to'the face of thewheel, a slide on which-the base is pivotally mounted, and means formoving the slide whereby the length of the tap to be presented to'thegrinding wheel may be varied.

7. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel, a tap holder, a .pivcted'base supporting thesame and i adapted to be'adjusted to position the tap at any desiredangle to the face ofv the wheel, means for .moving the pivot point ofthe base to thereby move the tap longitudinallyltoward or from the.wheel to the necessary position for the grinding operation and todetermine the length of the face of the lip to be ground, means forindexing the tap, means for rotating the same whereby successive lipsare brought to grinding position, and automatic means for causing thetap to move into the face of the wheel as each lip is being groundcausing the same to be ground to an increasing extent back of thecutting edge to provide clearance,

. 8. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel having a flat face, a tap holder, a head inwhich the holder is rotatable, a pivoted base supporting the headturnable to position a tap at any predetermined angle to the said faceof the wheel, means for moving the pivot point of the base transverselyof the axis of rotation of the grinding wheel to thereby determine thelength of the face of the lip to be ground means for causing continuousrotation of the holder whereby the lips of the tap are brought insuccession to grinding relation with the wheel, a cam on the holderrotatable in fixed relation therewith, said cam having a num ber of highpoints corresponding to the number of lips of the tap, and an elementfixed in position engaged by the cam to cause an oscillatory movement ofthe holder toward and from the wheel in timed relation with the rotationof the tap to cause afeed-in movement of the tap toward the grindingwheel as each lip is brought to grinding relation to thereby cause thetap to be ground to an increasing extent back of the cutting edge.

9. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel having a fiat grinding face, a tap holder, athead in which the holder is rotatable, a base for supporting the headand relative to which the head is osoillatable, said base being movableabout an axis to position a tap at any predetermined angle to the saidface of the grinding wheel and the axis of which is movable at a rightangle to the axis of rotation of the wheel to thereby present a greateror less length of the tap to the wheel, means for causing rotation ofthe holder whereby the lips of the tap are brought in succession togrinding relation with the wheel, a cam rotatable through rotation ofthe holder on the same axis and having a number of high and low pointsin succession corresponding to the number of lips of the tap, means foradjusting the tap with the cutting face of the lip in the necessaryrelation with a high point of the cam, a fixed element supported by thebase with which the cam engages whereby rotation of the cam causesoscillation of the head in a manner to cause the tap to move toward thewheel as each lip is brought to grinding relation to thereby cause thelip to be ground to an increasing extent back of its cutting edge.

10. In a machine for grinding taps having a plurality of lips, a.rotatable grinding wheel, a tap holder, a head in which the holder isrotatably mounted, means for rotating the holder, a base supporting thesaid holder in a manner to perrm't the same to oscillate about the axisof rotation-of the holder, said base being pivotally mounted to permitthe positioning of the tap at the desired angle to the grinding wheel,means for moving the pivot point to thereby present a greater or a lesslength of the tap from its point toward its shank to the grinding wheela series of cams each having a number of high points corresponding tothe number of lips of the tap,

said cams being rotatable through rotation of the holder and on the sameaxis, an element adapted to be brought to cooperative relation with anyone of the cams, the arrangement of the cams and said element and thehead being such that rotation of the cams causes an oscillation of thehead, means for adjusting the holder whereby the cutting edge of eachlip is in a predetermined relation with the high points of its cam,means for rotating the holder and tap to bring successive lips thereofto the grinding relation with the wheel, the face of the cam having acurve extending from each low to each high point eccentric to the'axisof rotation thereof and so positioned relative to the tap and saidelement cooperative with the cam that the tap is moved away from thegrinding face of the wheel as a lip comes to grinding position andthereupon as the high point of the cam passes the said element, the saidlip is moved into the face of the grinding wheel to grind the said lipeccentrically to its axis of rotation and to an increasing extent backof the cutting edge, and yieldable means for holding the cam in contactwith said element.

11. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel having a vertical grinding face, a rotatabletap holder, a base supporting the holder and pivoted to swing on avertical axis to position the tap at a desired angle to said grindingface of the wheel, means for variably positioning the pivot point of thebase to vary the length of the tap to be presented to the grindingwheel, a cam on the holder and rotatable therewith on the same axis,said cam having a series of high and low points each in number equal tothe number of lips of the tap and the shape of the face of the cam fromeach high to each low point being an arc eccentric to the axis ofrotation, means for positioning the lips of the tap in the necessaryrelationship to the high and. low points of the cam, means wherebyrotation of the cam causes an oscillation of the tap and holder towardand from the grinding face of the wheel, the arrangement being such thatas each lip is brought to grinding position, the arcuate face from ahigh toward a low point of the cam causes the tap to move toward thewheel as it is rotated and thus grind the said lip back of the cuttingedge eccentrically to its axis of rotation.

12. In a machine for grinding taps having a plurality of lips, arotatable grinding wheel, a tap holder a pivoted base therefor, meansfor adjusting the pivot point of the base to position the tap relativeto the wheel, means for rotating the holder and tap to bring successivelips thereof to grinding relation with a wheel, a cam supported by theholder and rotatable on the same axis as the tap, said cam having aseries of high and low points each equal in number to the number of lipsof the tap and the shape of the face from the cam from each high to eachlow point being an arc eccentric to the axis of rotation, means forpositioning the tap with the lips thereof in the necessary relationshipto the high and low points of the cam, means whereby ice rotation of thecam causes an oscillation of the substantially as described.

13. In a machine for grinding taps having a plurality of lips, a

rotatable grinding wheel, a

rotatable tap holder a pivotal support therefor, power means forrotating the grinding wheel, manual means for rotating the holder, a camhaving a series of high and low points each corresponding in number tothe number of lips of the tap, the shape of the face of the cam fromeach high to each low point being an arc eccentric to the axis ofrotation, means for positioning the cam with the points thereof incorrect relationship to the lips of the tap at the time the tap is ingauging position, means for automatically causing an oscillation of thetap toward and from the grinding wheel whereby as each lip is brought togrinding position it is caused to feed into the wheel as it reachesgrinding position and thus grind a clearance back of the cutting edge ofeach lip, means for adjusting the pivotal support to thereby positionthe tap longitudinally relative to the grinding wheel whereby thegrinding operation is performed upon a desired part of the tap, andmeans for adjusting the position of the tap angularly relative to thesurface of the grinding wheel comprising a pivotally mounted basesupporting the holder,

cams and related parts, and means for causing engagement of the tap andgrinding wheel while the tap and related parts are held from oscillatorymovement.

14. In a machine for grin-ding taps having a plurality of lips, agrinding wheel having a flat face, a frame member for supporting thewheel, a base member pivotally supported on the frame member, means forvarying the pivotal position of the base a tap holder supported on thebase in a manner to permit oscillatory movement about a horizontal axis,a cam supported by the oscillatory member and rotatable on the axis ofthe tap and holder at the same speed of rotation, operating means forrotating the tap holder and cams also carried by the base, meanssupported by the pivoted base and engageable by the cam to cause theholder to oscillate and thereby move the tap toward and from thegrinding wheel in such manner that each lip thereof is ground to anincreasing extent back of the cutting edge to provide clearance.

EDD C. OLIVER.

